This invention relates to a tree shear.
Mechanization of forestry operations is increasingly important with the high cost of labour encountered in industrialized countries and the difficulty in recruiting personnel willing to work in remote areas. An example of the mechanization trend has been the development of mechanized tree felling devices. Many different mechanical fellers have been patented including those using chain saws and others employing shearing blades. For example, U.S. Pat. No. 4,131,145 to Puna describes a tree cutting device with two opposed knife blades. These blades are curved to form a bowl when their cutting edges are in contact. U.S. Pat. No. 3,627,002 to Fulghum discloses a tree shear having a blade with a somewhat elliptical shape. Other similar devices are found in U.S. Pat. Nos. 3,986,541 to Mclaughlin, 4,061,167 to Dunn, 3,646,975 to McNeil and 3,837,382 to Gaitten. Other patents are discussed in an article entitled "Analysis of Shear Felling of Trees" by R. B. Golob in the December, 1976 Forest Management Institute Information Report FMR-X-93.
Despite the large amount of research and development carried out, large plate-like tree shears have'nt had much commercial acceptance. This is probably due to their large size and weight and the consequent difficulty of maneuvering them through the forest.